DE102010026367A1 - Venting facility for fuel tank of motor vehicle, has filter to accumulate and release gaseous hydrocarbons originating from fuel tank - Google Patents

Abstract

The venting facility has a filter (20) to accumulate and release gaseous hydrocarbons originating from the fuel tank (12), where a detection device (26) is provided to detect loading of a filter with gaseous hydrocarbons. A control unit (32) controls a combustion engine (22) of the motor vehicle. The control unit is designed to operate starting of the combustion engine of the motor vehicle for regenerating a filter, when the detection device detects a predetermined loading of the filter. An independent claim is also included for a method for operating a venting facility.

Description

The invention relates to a venting device for a fuel tank of a motor vehicle. The venting device comprises at least one filter for storing and releasing gaseous hydrocarbons originating from the fuel tank. By means of a detection device, a loading of the at least one filter with gaseous hydrocarbons can be detected. A control device is used to control an internal combustion engine of the motor vehicle. Furthermore, the invention relates to a method for operating such a venting device.

A venting device of the type mentioned is from the DE 100 01 060 C1 known. Here, an activated carbon container is coupled to a fuel tank and stores from this derived gaseous hydrocarbons. The activated carbon container is provided with two HC sensors, which serve to determine a loading of the activated carbon. The determined values are transmitted to an electronic engine control unit. A regeneration line of the activated carbon container has a tank ventilation valve. In a line leading from the tank-venting valve to an intake tract of an internal combustion engine, a valve and a diaphragm pump are arranged. When the HC sensors detect a certain charcoal load, the valve is opened and the diaphragm pump applies an additional air-fuel mixture to the fresh air intake internal combustion engine. The engine control unit provides the appropriate timing of the tank vent valve and controls the engine so that nevertheless a certain air-fuel ratio is maintained.

The DE 10 2008 016 079 A1 describes a venting device for a fuel tank of a motor vehicle, in which a vent line connects the fuel tank with a first activated carbon filter, which receives refueled fuel vapors during refueling of the fuel tank from the fuel tank. A second activated carbon filter, which is also coupled via the vent line to the fuel tank, then absorbs fuel vapors when the motor vehicle is running or parked. The two activated carbon filters arranged upstream in the vent line switching valve, which optionally allows venting of the fuel tank via the first activated carbon filter or the second activated carbon filter. The switching valve is in this case z. B. actuated when a fuel cap is opened or a fuel nozzle is inserted into a filler neck of the fuel tank.

The US 5 111 795 A also describes a venting device for a fuel tank of a vehicle in which a vent line of the fuel tank branches to two groups of activated carbon filters. A switching device releases an inlet pipe to the first group of activated carbon filters when a pressure sensor in a filler pipe of the fuel tank detects an atmospheric pressure. After refueling, the second group of activated carbon filters is then used again to receive fuel vapors from the fuel tank.

In particular, in hybrid vehicles, it is a challenge to avoid that gaseous hydrocarbons escape from the fuel tank or the activated carbon filter, since the vacuum used to regenerate the activated carbon filter in the intake manifold of the engine is only available when the internal combustion engine is operated. In the purely electric driving operation of a hybrid vehicle, it comes without countermeasures to a leakage of hydrocarbons from the activated carbon filter.

In order to achieve particularly low emissions from the fuel tank or from the activated carbon filter with respect to gaseous hydrocarbon, it is known from the prior art to manufacture the fuel tank as a pressure tank made of sheet metal. However, this is associated with relatively high costs. In addition, a sheet metal tank heats up relatively quickly when exposed to heat, so that comparatively much fuel evaporates, which must be stored in the activated carbon filter.

Object of the present invention is to provide a venting device of the type mentioned above and a method for operating such a venting device, which or which makes it possible to avoid leakage of gaseous hydrocarbons from the venting in the environment in a simple manner particularly largely.

This object is achieved by a venting device with the features of patent claim 1 and by a method for operating a venting device having the features of patent claim 12. Advantageous embodiments with expedient developments of the invention are specified in the dependent claims.

In the venting device according to the invention, the control device is designed to cause the regeneration of the at least one filter starting the internal combustion engine of the motor vehicle when the detection device detects a predetermined loading of the at least one filter. So it will be timely countermeasures by starting the engine taken before the loading of the at least one filter reaches an order of magnitude in which an uncontrolled leakage of gaseous hydrocarbons from the filter into the environment would be feared.

If only one filter is provided, it then takes up gaseous hydrocarbons when fuel is introduced into the fuel tank of the motor vehicle. Furthermore, gaseous hydrocarbons also enter the filter during driving of the motor vehicle and at its stoppage. In particular, if now the motor vehicle is several days long or - when training as a hybrid vehicle - drives only electrically driven, is in the intake manifold of the engine no vacuum for purging the filter available, and the loading of the filter increases. This can be detected by means of the detection device. By means of the control device can then be provided for starting the internal combustion engine to pressurize the filter with a negative pressure, which ensures the entry of a flushing medium into the filter and thus for discharging gaseous hydrocarbons therefrom. However, it can also be done in other ways rinsing the filter, such as by introducing compressed air.

In a hybrid vehicle, the controller may be configured to initially provide for starting the engine, as long as the hybrid vehicle is being electrically powered, and then triggering regeneration thereof by pressurizing the filter with negative pressure. Thus, a user of the motor vehicle does not need to start the internal combustion engine himself, but the starting is initiated by the control device when the detection device detects the predetermined load. Even if the motor vehicle has only the internal combustion engine for its drive, the starting of the internal combustion engine can bring about a regeneration of the filter after a longer service life and, consequently, a prolonged accumulation of gaseous hydrocarbons in the filter.

In particular, a sensor may be used as detection device, which is arranged in the filter. Additionally or alternatively, the loading of the filter can be modeled, wherein the operation of the motor vehicle and the outside temperature can be taken into account to detect the load.

The control device can be designed in an advantageous manner to prevent a decommissioning of the internal combustion engine, as long as a predetermined loading of the at least one filter is not exceeded. This prevents the internal combustion engine from being put into operation at too short intervals. In a hybrid vehicle, the release of the purely electric drive accordingly takes place only when the at least one filter has only a slight charge of gaseous hydrocarbons.

In a further advantageous embodiment of the invention, the venting device comprises a first and a second filter for storing and releasing originating from the fuel tank gaseous hydrocarbons. The first filter is coupled to the fuel tank so as to store gaseous hydrocarbons when fuel is introduced into the fuel tank. In this case, only the loading of the second filter with gaseous hydrocarbons can be detected by means of the detection device.

Thus, the first filter only needs to absorb gaseous hydrocarbons when fuel is introduced into the fuel tank of the motor vehicle, while gaseous hydrocarbons reach the second filter at least predominantly when the motor vehicle is driving and when it is stationary. Consequently, when the motor vehicle is stationary for several days or merely driven electrically, the loading of the second filter increases. It is now sufficient to detect this load by means of the detection device in order to be able to initiate countermeasures in good time.

Here, in an advantageous embodiment of the invention, the detection device is coupled to the control device such that a regeneration of the second filter in response to its load can be triggered. Namely, the regeneration of the second filter reduces its loading. If the internal combustion engine of the motor vehicle is currently in operation, it is sufficient to trigger the regeneration, to pressurize the second filter with negative pressure, which is available in the intake manifold of the internal combustion engine.

As a further advantage, it has been shown that by means of the control device, a regeneration of the first filter in response to the loading of the second filter can be triggered. Thus, the control device can ensure that initially the second filter is regenerated sufficiently far before the first filter is subjected to a flushing medium, in particular fresh air, in order to reduce the loading of the first filter with gaseous hydrocarbons. This is based on the finding that when operating the motor vehicle, the first filter is used less frequently than the second filter, namely only when fuel is introduced into the fuel tank. Therefore, it is also sufficient to regenerate the first filter less often. The first filter is here designed so that it is the one at Refueling from the fuel tank displaced gaseous hydrocarbons can absorb, even if the fuel tank when refueling at least half, in particular three quarters, filled.

In a further advantageous embodiment of the invention, the venting device comprises a shut-off device for preventing the introduction of gaseous hydrocarbons from the fuel tank into the second filter during refueling. The shut-off device can in particular be arranged in a connecting line connecting the fuel tank to the second filter, which is also referred to as a tank line. By means of the shut-off device, it can be particularly effectively prevented during fueling of the fuel tank that gaseous hydrocarbons displaced from the fuel tank can enter both the first filter and the second filter. In other words, it can be ensured that during refueling only the first filter absorbs gaseous hydrocarbons. The shut-off device is preferably opened in an electrically non-energized state, so that no pressure can build up in the fuel tank in this operating state.

It is advantageous if the venting device has at least one valve device for releasing a respective regeneration line of the two filters. It is particularly simple when each of the two Regenerierleitungen a valve is arranged separately, since so comparatively simple and inexpensive separately controllable valves can be used. However, it is also possible to provide a valve device which can optionally effect an opening of the regeneration line of the first filter or an opening of the regeneration line of the second filter. Such a common valve device for both regeneration lines takes up very little space.

In a further advantageous embodiment of the invention, a connection line connecting the fuel tank to the first filter has a larger cross-section through which a cross-section than the connecting line connecting the fuel tank with the second filter. It can be introduced comparatively quickly fuel in the fuel tank, and the fuel vapors can pass relatively unhindered over the so-called tank line connecting line to the first filter. In contrast, it is sufficient to provide a smaller flow-through cross section for the leading to the second filter tank line. In the operating state of the fuel tank, which is different from refueling, a lower volume flow of escaping fuel vapors can be expected, which are stored in the second filter. Moreover, the comparatively small flow-through cross-section of the tank line leading to the second filter very largely prevents gaseous hydrocarbons from entering the second filter during refueling without the need for a shut-off valve being provided for this purpose.

The first filter and the second filter may have mutually different gaseous hydrocarbon receiving capacities. A comparatively large absorption capacity of the first filter makes it possible to store gaseous hydrocarbons even if the still comparatively full fuel tank is refueled, even if the first filter was not or hardly regenerated before refueling. On the other hand, since the load of the second filter is detected, it can be purged if necessary, and need not have an unnecessarily large reserve of reserve capacity. If, however, the second filter has a larger absorption capacity than the first one, this makes it possible to store gaseous hydrocarbons over a particularly long period of time. Then, the second filter must be regenerated less frequently, resulting in a reduced aging of the second filter.

It is furthermore advantageous if the venting device comprises a shut-off device by means of which a fresh-air inlet of the first filter is shut off in an electrically non-excited state of the shut-off device. To open the fresh air inlet, the shut-off device can be converted into an electrically excited state. This ensures that in the electrically non-energized state of the shut-off device gaseous hydrocarbons can not escape from the first filter via the fresh air inlet into the environment. The first filter is thus closed to its fresh air side after refueling of the fuel tank by the shut-off device is not electrically excited.

Finally, it has proven to be advantageous if the venting device comprises a shut-off device, by means of which a fresh air inlet of the second filter is shut off in an electrically excited state of the shut-off device. As a result, with electrically non-energized shut-off device at the fresh air inlet of the second filter to the pressure of the fresh air corresponding pressure, ie usually atmospheric pressure, and it can be flushed by applying a negative pressure of this with fresh air. In the electrically excited state, the shut-off device ensures that no gaseous hydrocarbons can penetrate into the second filter via a connecting line connecting the second filter with the fuel tank, which is also referred to as a tank line. On too This way it can be ensured that during refueling only the first filter absorbs gaseous hydrocarbons.

In the method according to the invention for operating a venting device for a fuel tank of a motor vehicle, at least one filter stores gaseous hydrocarbons originating from the fuel tank. By means of a detection device, a loading of the at least one filter with gaseous hydrocarbons is detected. For regenerating the at least one filter, starting of an internal combustion engine of the motor vehicle is effected when the detection device detects a predetermined loading of the at least one filter. Thus, leakage of gaseous hydrocarbons from the venting device into the environment can be avoided in a simple manner.

In an advantageous embodiment of the method, gaseous hydrocarbons originating from the fuel tank are fed into a first filter when refueling the fuel tank. At least in an operating state of the fuel tank different from refueling, gaseous hydrocarbons originating from the fuel tank are conducted into a second filter. The loading of the second gaseous hydrocarbon filter is detected, and the second filter is regenerated when a predetermined load is detected. So it just needs the loading of one of the two filters to be monitored to prevent leakage of gaseous hydrocarbons into the environment.

The advantages and preferred embodiments described for the venting device according to the invention also apply to the method according to the invention and vice versa.

The features and feature combinations mentioned above in the description as well as the features and feature combinations mentioned below in the figure description and / or shown alone in the figure can be used not only in the respectively specified combination but also in other combinations or alone, without the scope of To leave invention.

Further advantages, features and details of the invention will become apparent from the claims, the following description of preferred embodiments and from the drawings. Showing:

1 schematically a first embodiment of a venting device for a fuel tank of a motor vehicle, wherein the fuel tank is coupled to only one activated carbon filter; and

2 schematically a second embodiment of a venting device for the fuel tank, which is coupled to two activated carbon filters.

A venting device 10 for a fuel tank 12 a motor vehicle, which is in particular a hybrid vehicle with an internal combustion engine 22 and an electric drive (not shown) may include an activated carbon filter 20 , which also has a tank line 18 designated connecting line with the fuel tank 12 connected is. The activated carbon filter 20 acts as a so-called refueling activated carbon filter and at the same time as an operating carbon filter. The activated carbon filter 20 Namely serves to then take up gaseous hydrocarbons when the fuel tank 12 is filled via a (not shown) filler pipe with fuel and so gaseous hydrocarbons from the fuel tank 12 be displaced. The activated carbon filter 20 But it also helps in refueling the fuel tank 12 different operating conditions from the fuel tank 12 to receive originating gaseous hydrocarbons.

These can be released from the fuel when the fuel tank 12 due to high outside temperature or due to the operation of the internal combustion engine 22 of the motor vehicle is thermally stressed. Even when the motor vehicle is at a standstill, fuel which evaporates in the activated carbon filter evaporates 20 is stored. Even if in training of the motor vehicle as a hybrid vehicle while driving the internal combustion engine 22 is not in operation, but only provides the electric drive for moving the motor vehicle, get gaseous hydrocarbons in the activated carbon filter 20 ,

By means of a sensor 26 becomes a load of the activated carbon filter 20 supervised. The in the activated carbon filter 20 integrated sensor 26 detects a concentration of gaseous hydrocarbons in the activated carbon filter 20 , Via a regeneration line 28 can the second activated carbon filter 20 be subjected to a negative pressure, which in a (not shown) intake manifold of the internal combustion engine 22 prevails when the internal combustion engine 22 Suction combustion air. For this purpose, a in the Regenerierleitung 28 arranged tank vent valve 30 , in particular clocked, opened. The activated carbon filter 20 has a fresh air inlet 34 on which fresh air flows into this, when the tank vent valve is open 30 the internal combustion engine 22 Suction combustion air. The tank vent valve 30 is from a controller 32 controlled, which with the sensor 26 is coupled and so the loading of the activated carbon filter 20 can evaluate.

If then a predetermined loading of the activated carbon filter 20 is reached, and thereby the internal combustion engine 22 is not in operation anyway, the activated carbon filter 20 regenerated by the internal combustion engine 22 is started. Starting the internal combustion engine 22 is via the controller 32 causes, which can be designed in particular as an engine control unit. Alternatively, the control device 32 transmit a corresponding command to an engine control unit (not shown).

The activated carbon filter 20 is designed to store gaseous hydrocarbons over several days. This is particularly favorable if the motor vehicle is a hybrid vehicle which can be driven purely electrically over a comparatively long period of time. In particular, in a hybrid vehicle in which the traction battery is rechargeable by connecting to a vehicle external power source, it may well happen that the vehicle user operates the hybrid vehicle purely electrically over a relatively long period of time. During this time gaseous hydrocarbons accumulate in the activated carbon filter 20 , This is then by starting the engine 22 counteracted when the activated carbon filter 20 has reached a predetermined loading.

Because of the activated carbon filter 20 is regenerated depending on its load, the fuel tank 12 comparatively inexpensive and easy to be manufactured as a non-pressure tank made of plastic, in contrast to a pressure tank made of a metal. This makes it possible to keep the costs of the motor vehicle, in particular the hybrid vehicle, low.

A second embodiment (cf. 2 ) a venting device 10 ' for the fuel tank 12 includes a first activated carbon filter 14 , which is operated as a refueling activated carbon filter. This activated carbon filter 14 Namely serves to then take up gaseous hydrocarbons when the fuel tank 12 is filled via a (not shown) filler pipe with fuel and so gaseous hydrocarbons from the fuel tank 12 be displaced. One the activated carbon filter 14 with the fuel tank 12 connecting tank line 16 has a comparatively large flow-through cross-section, and has, for example, an inner diameter of 13 mm.

About a second tank line 18 ' is the fuel tank 12 with a second activated carbon filter 20 ' connected. The tank line 18 ' need only have a comparatively small flow-through cross-section, and has, for example, an inner diameter of 6 mm. The second activated carbon filter 20 ' is operated as an operating carbon filter and serves to refuel the fuel tank 12 different operating conditions from the fuel tank 12 to receive originating gaseous hydrocarbons.

So when refueling the fuel tank 12 the from the fuel tank 12 displaced gaseous hydrocarbons exclusively into the first activated carbon filter 14 enter is in the tank line 18 ' leading to the second activated carbon filter 20 ' leads, a shut-off device 24 intended. The shut-off device 24 is open in the present case, if it is not charged with electric current. With the shut-off device open 24 can gaseous hydrocarbons from the fuel tank 12 in the second activated carbon filter 20 ' so that the pressure in the fuel tank 12 does not rise above atmospheric pressure.

By means of the sensor 26 is in the second embodiment of the venting device 10 ' the loading of the second activated carbon filter 20 ' supervised. About the regeneration line 28 can the second activated carbon filter 20 ' be subjected to a negative pressure, which in a (not shown) intake manifold of the internal combustion engine 22 prevails when the internal combustion engine 22 Suction combustion air. This is done in the regeneration line 28 arranged tank vent valve 30 , in particular clocked, opened. The tank vent valve 30 is from the controller 32 controlled, which with the sensor 26 is coupled and so the loading of the second activated carbon filter 20 ' can evaluate.

This is because the second activated carbon filter 20 ' is regenerated depending on its load, the fuel tank 12 comparatively inexpensive and easy to be manufactured as a non-pressure tank made of plastic, in contrast to a pressure tank made of a metal.

The fresh air intake 34 of the second activated carbon filter 20 ' can be a shut-off valve 36 which is open when it is not subjected to electric current. With the tank vent valve open 30 then takes care of the second activated carbon filter 20 ' over the fresh air intake 34 incoming fresh air for regeneration of the activated carbon filter 20 ' , The open shut-off valve 36 In addition, ensures that in the fuel tank 12 does not build up pressure above atmospheric pressure. While refueling the fuel tank 12 becomes the shut-off valve 36 closed to prevent gaseous hydrocarbons through the tank line 18 ' in the second activated carbon filter 20 ' reach.

The shut-off valve 36 may additionally or alternatively to that in the tank line 18 ' arranged shut-off device 24 be provided. If neither the shut-off valve 36 still the shut-off device 24 are present, ensures the small diameter of the tank line 18 ' that at most a small amount of gaseous hydrocarbons when refueling in the second activated carbon filter 20 ' can get.

In the present case, after starting the internal combustion engine 22 So if in the suction pipe negative pressure for venting the activated carbon filter 20 ' . 14 is available, first the second activated carbon filter 20 ' flushed with fresh air. This takes place until the loading of the second activated carbon filter 20 ' is sufficiently reduced.

Subsequently, the tank vent valve 30 closed, and one in a regeneration line 38 of the first activated carbon filter 14 arranged second tank vent valve 40 will be opened. The control device 32 thus controls the tank ventilation valve 40 so on, that the activated carbon filter 14 with the in the intake manifold of the engine 22 prevailing negative pressure is applied. At the same time a shut-off valve 42 electrically energized and opened, allowing fresh air through a fresh air inlet 44 in the first activated carbon filter 14 can occur.

Rinsing the first activated carbon filter 14 following rinsing of the second charcoal filter 20 ' ensures that the activated carbon filter 14 gaseous hydrocarbons can resume, such as when still comparatively full fuel tank 12 Fuel is refueled.

When the internal combustion engine 22 after rinsing the first activated carbon filter 14 is still in operation, can in the intake manifold of the engine 22 applied negative pressure can be used again the second activated carbon filter 20 ' to apply fresh air and so on or free again of gaseous hydrocarbons. The activated carbon filter 20 ' is preferably designed to be able to store gaseous hydrocarbons for at least three days without the combustion engine in between 22 must be put into operation. In winter outside temperatures, the activated carbon filter 20 ' then even much longer from the fuel tank 12 Store escaping fuel vapors.

If then a predetermined loading of the second activated carbon filter 20 ' reached is the second activated carbon filter 20 ' regenerated by the internal combustion engine 22 is started. This is done via the controller 32 causes, or the controller 32 can transmit a corresponding command to an engine control unit.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 10001060 C1 [0002]
• DE 102008016079 A1 [0003]
• US 5111795 A [0004]

Claims (13)

Ventilation device for a fuel tank ( 12 ) of a motor vehicle, with at least one filter ( 14 . 20 . 20 ' ) for storing and releasing from the fuel tank ( 12 ) gaseous hydrocarbons, with a detection device ( 26 ) for detecting a loading of the at least one filter ( 20 . 20 ' ) with gaseous hydrocarbons, and with a control device ( 32 ) for driving an internal combustion engine ( 22 ) of the motor vehicle, characterized in that the control device ( 32 ) is designed to regenerate the at least one filter ( 20 . 20 ' ) starting the internal combustion engine ( 22 ) of the motor vehicle when the detection device ( 26 ) a predetermined loading of the at least one filter ( 20 . 20 ' ) detected. Venting device according to claim 1, characterized in that the control device ( 32 ) is designed to stop the internal combustion engine ( 22 ) until a predetermined loading of the at least one filter ( 20 . 20 ' ) is below. Venting device according to claim 1 or 2, characterized in that the venting device comprises a first and a second filter ( 14 . 20 ' ) for storing and releasing from the fuel tank ( 12 gaseous hydrocarbons, the first filter ( 14 ) so with the fuel tank ( 12 ) when fuel is introduced into the fuel tank ( 12 ) stores gaseous hydrocarbons, and wherein by means of the detection device ( 26 ) only the loading of the second filter ( 20 ' ) is detectable with gaseous hydrocarbons. Venting device according to claim 3, characterized in that the detection device ( 26 ) in such a way with the control device ( 32 ), that the regeneration of the second filter ( 20 ' ) is triggered depending on its load. Venting device according to claim 3 or 4, characterized in that by means of the control device ( 32 ) a regeneration of the first filter ( 14 ) as a function of the loading of the second filter ( 20 ' ) is triggered. Venting device according to one of claims 3 to 5, characterized by a shut-off device ( 24 ) for inhibiting introduction of gaseous hydrocarbons from the fuel tank ( 12 ) into the second filter ( 20 ' ). Venting device according to one of claims 3 to 6, characterized by at least one valve device ( 30 . 40 ) for releasing a respective regeneration line ( 28 . 38 ) of the two filters ( 14 . 20 ' ). Venting device according to one of claims 3 to 7, characterized in that a fuel tank ( 12 ) with the first filter ( 14 ) connecting connecting line ( 16 ) has a larger cross-section through which the fuel tank ( 12 ) with the second filter ( 20 ' ) connecting connecting line ( 18 ). Venting device according to one of claims 3 to 8, characterized in that the first filter ( 14 ) and the second filter ( 20 ' ) have different receiving capacities for gaseous hydrocarbons. Venting device according to one of claims 3 to 9, characterized by a shut-off device ( 42 ) for shutting off a fresh air inlet ( 44 ) of the first filter ( 14 ) in an electrically non-energized state of the shut-off device ( 42 ). Venting device according to one of claims 3 to 10, characterized by a shut-off device ( 36 ) for shutting off a fresh air inlet ( 34 ) of the second filter ( 20 ' ) in an electrically excited state of the shut-off device ( 36 ). Method for operating a venting device ( 10 ) for a fuel tank ( 12 ) of a motor vehicle, in which at least one filter ( 14 . 20 . 20 ' ) from the fuel tank ( 12 ) stores gaseous hydrocarbons, wherein by means of a detection device ( 26 ) a loading of the at least one filter ( 20 . 20 ' ) is detected with gaseous hydrocarbons, characterized in that by means of a control device ( 32 ) for regenerating the at least one filter ( 20 . 20 ' ) starting an internal combustion engine ( 22 ) of the motor vehicle when the detection device ( 26 ) a predetermined loading of the at least one filter ( 20 . 20 ' ) detected. A method according to claim 12, characterized in that when fueling the fuel tank ( 12 ) from the fuel tank ( 12 gaseous hydrocarbons into a first filter ( 14 ) and at least in a non-refueling operating state of the fuel tank ( 12 ) into a second filter ( 20 ' ) whose charge is detected with gaseous hydrocarbons and which is regenerated when a predetermined load is detected.

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